Functionally terminated liquid polymers, also referred to herein as telechelic liquid polyethers, are well known commercially. In particular, telechelic epihalohydrin liquid polymers are currently being used as a toughening additive for reinforced unsaturated polyesters and thermoset polyesters, as a component of polyurethanes, as a component of non-solvent adhesives, as an impermeable and weatherable coating, and as an energetic binder as in rocket fuels.
Formation of cyclic oligomers, however, is a characteristic feature of the cationic ring-opening polymerization of cyclic ethers. In some cases, cyclic oligomers are the predominant products of the polymerization. Telechelic epihalohydrin liquid polymers are no exception and contain varying amounts of oligomers. The amount of cyclic oligomers is dependent on the nature of the cationic catalyst, polymerization conditions, and the molecular weight of the liquid polymer. For instance, the epihalohydrin liquid polymers can contain up to about 40% by weight of cyclic oligomers although liquid polymers of epihalohydrin generally contain about 5-20% by weight of oligomers. The presence of cyclic oligomers is undesirable in some applications. Since cyclic oligomers contain no functionality and their molecular weights are low, they may be useless for the intended purposes and may degrade the properties of the final products. The removal of nearly all or a portion of cyclic oligomers from polyethers can be accomplished pursuant to the invention described herein.